1. Technical Field
The present invention relates to a method for driving an electrophoretic display device. In addition, the invention relates to an electrophoretic display device that is driven by the driving method. The invention further relates to an electronic apparatus that is provided with an electrophoretic display device that is driven by the driving method.
2. Related Art
An electrophoretic display device has an image display unit, which is an image display area made up of a plurality of pixels. Having the plurality of pixels, a typical electrophoretic display device of related art performs image display as follows. In each of the plurality of pixels, an image signal is written into a memory circuit through a pixel-switching element. A pixel electrode is driven as a result of the application of a pixel voltage thereto, the level of which is in accordance with the written image signal. As the pixel electrode is driven, an electric potential difference arises between the pixel electrode and the common electrode. An electrophoretic display element that is sandwiched between the pixel electrode and the common electrode is driven because of the voltage level difference that has arisen between the pixel electrode and the common electrode. In this way, an electrophoretic display device of the related art performs image display. As an example of such an image display apparatus of the related art, JP-A-2003-84314 discloses an electrophoretic display device that has a plurality of pixels in each of which a dynamic random access memory (DRAM) is provided as a memory circuit.
In a typical electrophoretic display technique of the related art explained above, the rewriting of an original image is performed by making the electric potential of the pixel electrode different from that of the common electrode in each of the plurality of pixels. That is, a voltage level difference arises between the pixel electrode and the common electrode in all pixels for each time when an image display switchover occurs. This means that the entire image changes over due to the application of voltages to the pixel electrodes and the common electrode in all of the plurality of pixels even when it is only a part of the image that needs to be actually changed. For this reason, a driving scheme of the related art has a technical disadvantage in that it inevitably results in high power consumption. In addition, it has another technical disadvantage in that the degradation of the electrophoretic display element is accelerated. Moreover, it has still another technical disadvantage in that it invites the degradation of image quality due to the successive writing of the same gradation (e.g., gray scale) into a pixel.